Foraminiferal and Calcareous Nannofossils Biostratigraphy of Krishna-Godavari Deep Water Wells

Qazi A. Ali¹, Baruah Pallav², Kapoor Pushkar¹, Baruah Joyshree², Sinha Sujay¹, and Shukla Sudhir^1
1KDMIPE, ONGC, Dehradun, India
²ERBC, ONGC, NAZIRA, India

The deep water sector of K.G. Basin constitutes strategic area for future growth of ONGC through reserve accretion. ONGC has drilled several wells in deep water, K.G Basin and has met with few successes for enhanced exploration. Basic data generation in laboratories and geoscientific data integration to understand geology of area are of prime importance during the initial phase of exploration. Biostratigraphic study on deep water wells with help of STRATABUGS software for plotting faunal frequency, ranges, zones, age and interpreted geological data along with logs lead to the generation of key inputs in formulation of deep water geological models.

Four wells viz. KG-1, KG-2, KG-3 and KG-4 were studied for comprehensive multi-microfossil biostratigraphy based on foraminifera and calcareous nannofossils. The sediments are rich in foraminifera and poor in nannofossils and palynomorphs & range from Early Pliocene to Recent age. Early / Late Pliocene boundary is marked on the basis of LAD of Neogloboquadrina acostoensis and Plio / Pleistocene boundary on LAD of Pulleniatina praecursor. Pliocene sediments were deposited in slope - basin floor complex in upper to middle bathyal conditions. Mixing of fauna from shallow shelf to deep water is also observed at certain intervals. In wells KG-3, KG-4, KG-2 shallowing of bathymetry from Early Pliocene is observed, while in KG-1 deeper bathymetry is observed probably due to differential rates of sediment supply and accommodation creation between different sectors.

Presentation GEO India Expo XXI, Noida, New Delhi, India 2008©AAPG Search and Discovery